Lake Michigan waters heat up this summer

Temperature recorded at 80 degrees, the highest it's been since 2001

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Lake Michigan isn't known for its bathwater-like temperatures, but this summer the Great Lake seems almost tropical.

Water temperatures climbed to 80 degrees Sunday afternoon and early evening at a buoy stationed in the middle of the lake - the first time it reached 80 since 2001, according to the National Weather Service.

The highest temperature ever recorded at the buoy on the southern end of the lake, located 40 miles offshore of Racine, was 81 on Aug. 18, 1995.

A warm Lake Michigan is likely to mean a mild fall for areas along the shoreline because the amount of cooling from breezes coming off the lake will be minimized by the balmy water, said Jeff Craven, science and operations officer for the National Weather Service bureau in Sullivan.

It also could mean more lake-effect snow this winter for communities on the eastern side of the lake.

It's no surprise the lake is warm. In June, the average daily temperature in Milwaukee was 3.6 degrees higher than the average in July. Plus, there has been loads of sun shining down on the water.

"The amount of sunshine and the warmth overland is pretty much proportional to how warm the lake is going to get," Craven said.

It's the humidity

There are two other factors affecting a toasty Lake Michigan: high humidity and relatively calm water conditions this summer, noted Russell Cuhel, a senior scientist at the Great Lakes WATER Institute in Milwaukee.

On many days, Lake Michigan seems more like a mirror, or the waves are only 1 to 2 feet. Calm conditions lead to more heating at the surface because there's no turbulence to mix surface water with colder water from deeper in the lake, said Carmen Aguilar, an associate scientist at the institute.

And high humidity allows heat to pass through the lake at a much greater rate and cuts down on evaporation, Cuhel said.

"One of the things you certainly have more of is fog. When the lake is warm and you get a north wind that's cool, then you can get quite a bit of fog you don't normally get," Cuhel said.

Affects fish, too

The distribution of fish, ranging from perch to alewives, is affected by water temperature.

When Lake Michigan is warmer than normal, fish that like the cold such as perch will head to a depth that feels comfortable to them. Plankton are likely loving the 80-degree water.

"Anything that grows out there, their growth rates depend on temperatures," said Bill Horns, a Great Lakes fisheries specialist for the state Department of Natural Resources. "The warmer it is, the faster it goes - to a point. So it makes a difference, just like your grass grows faster when it's warm."

About Meg Jones

Meg Jones is a general assignment reporter who specializes in military and veterans issues. Meg was part of a team that was a Pulitzer Prize finalist in 2003, and has been honored by the Milwaukee Armed Forces Committee for her coverage.